A 61-year-old New Zealand sailor facing sex and assault charges in Vanuatu has disappeared, and police are seeking public help to find him.

Port Vila serious crime detectives arrested Vivian Archie Smith, when he sailed his yacht into Port Vila harbour on May 30.

A young Solomon Islands woman aboard his yacht was allegedly attacked by Smith before being rescued by the crew of a fishing boat and taken ashore, police said.

Smith, also known as Tony Smith, was released on bail to appear in Port Vila Magistrates Court on June 13, but failed to appear.

The Port Vila Presse reported today that under his bail conditions, Smith was supposed to surrender his passport to police and report to Port Vila police station three times a week.

The paper quoted Detective Inspector Delphine Vuti as saying that as long as Smith kept to those conditions he was allowed to live aboard his yacht, the Seascamp.

But before his court appearance the yacht slipped its mooring, left the marina and did not return.

Ms Vuti said police in other Pacific countries had been alerted, but Smith had left behind his passport and might still be sailing in Vanuatu waters.